function Map(el){
    //保存地图对象
    this.el = el
    //console.log('map',this.el)
    //记录地图相关属性
    this.width = 800
    this.height = 400
}

Map.prototype.create = function(){
    //设置地图的宽高
    this.el.style.width = this.width + 'px'
    this.el.style.height = this.height+ 'px'
    //给地地图加背景图片
    this.el.style.background = 'url(./bg.png)'
    //给地图加边框
    this.el.style.border = '10px solid green'
    this.el.style.position = 'relative'

}